The interaction of pesticides which when applied in combination, either simultaneously or sequentially, result in responses not predictable from the performance of each pesticide applied singly is of major concern to agriculturalists. Of particular concern are synergistic responses which occur on a single plant species. Synergistic responses obtained with combinations of herbicides, insecticides and fungicides are described as the combined action of two components of a mixture such that the total effect is greater or more prolonged than the sum of the effects of the two components taken independently.
Simultaneous or sequential applications of herbicides, fungicides and insecticides are common in the production of many food and fiber crops; however, synergistic pesticide combinations may cause problems in crop production due to increased toxicity to crop plants and other nontarget species and increased residue burdens in crops or soil.
Methods directed towards protecting a crop from inhibition of growth and development due to a single pesticidal compound, such as an herbicide, are found in U.S. Pat. Nos. 4,343,649 and 3,749,566 and in copending patent applications Ser. Nos. 292,207 filed Dec. 30, 1988 and 169,094 filed Mar. 8, 1988. However, no methods directed towards protecting or preventing a crop from injury due to a combination of pesticidal compounds have been described.
It is, therefore, an object of this invention to provide a method for protecting or preventing a crop from injury due to the application of a combination of pesticidal compounds by altering the susceptibility of the crop to one or more components of the combination by incorporating a pesticide resistance gene into the genome of the crop.